Brush construction

ABSTRACT

Rotary brushes formed with brush components comprising a bundle of bristle material bound and tightly compacted at one end by a uniformly corrugated metal band, the other end of such bristle bundle extending from the corrugated band to form a composite generally circular brush face, including rotary end brushes and rotary wheel brushes of substantially unitary design and also of a plurality of end-to-end interlocking annular brush elements; further including the foregoing brushes with plastic holder portions; and, further including the foregoing brushes with convexly curved elastomeric collars, such as O-rings encircling the bristles inside the holders.

United States Patent Schofield Feb. 15,1972

[541 BRUSH CONSTRUCTION [72] Inventor: Arthur T. Schofield, Brecksville,Ohio [73] Assignee: The Manulacturers Brush Company,

Cuyahoga, Ohio 221 Filed: Oct. 6,1969 [21 Appl.No.: 863,779

1,928,990 10/1933 Barnettet al. ..l5/190 Peterson 15/180 Wiseman 15/180Williamson et al. ..15/183 Primary Examiner-Peter Feldman Attomey-McCoy,Greene & Howell [57] ABSTRACT Rotary brushes formed with brushcomponents comprising a bundle of bristle material bound and tightlycompacted at one end by a uniformly corrugated metal band, the other endof such bristle bundle extending from the corrugated band to form acomposite generally circular brush face, including rotary end brushesand rotary wheel brushes of substantially unitary design and also of aplurality of end-to-end interlocking annular bl'LlSh elements; furtherincluding the foregoing brushes with plastic holder portions; and,further including the foregoing brushes with convexly curved elastomericcollars, such as O-rings encircling the bristles inside the holders.

24 Claims, 10 Drawing Figures mtufturmsmra I v 3.641.611

' INVENTOR. ARTHUR T. SCHOFIELD ATTORNEY PATENTEUFEBYSIQYZ I I 3.641.6l1

SHEET 2 OF 2 8 32 FIG. 9

FIG. IO

INVENTOR. ARTHUR T SCHOFIELD BY Ma 60, Gaeene a awell ATTORNEYS BRUSHCONSTRUCTION BACKGROUND AND SUMMARY OF INVENTION This invention relatesto brush construction wherein a rigid corrugated metal band is employedto tightly bind bristle material to form a bristle cartridge formounting in a holder to form a power-driven industrial rotary end brushand other rotary brushes. 7

In the manufacture of power-driven industrial rotary brushes, it isessential to mount the bristle material securely in the bristle holderto prevent the bristle. material from loosening and flying out of theholder in use.

A number of different techniques have been employed to this end. Oneconstruction has been to wrap the bristles about an anchor ring ,orother retaining member in the base of the holder. Another constructionhas been to hold the bristles with a quantity of solder in the base ofthe holder cup.

Nevertheless, a variety of problems have been encountered inconstructions of these types, including the weakening of bristlesundergoing a sharp flex at the retaining member, loss of temper bybristles subjected to soldering temperatures, uneven fill distribution,and the difficulty and expense of subsequently trimming the brush to atrue flat face.

I have found that I can overcome these problems by enclosing one end ofa bundle of brush bristle material with a deformable metal band anddeforming that band inwardly at regularly spaced intervals to formuniform corrugations therein, thereby tightly compacting one end of thebristle bundle in a uniformly corrugated metal band so that the otherend of the bristle bundle extends from the band to provide a compositegenerally circular brush face.

In the past, persons have bound brush bristle material into bundles ortufts of various sizes and shapes prior to mounting in various holders,as may be seen by reference to US. Pat. Nos. 2,202,292; 2,421,647;3,312,993; and 3,380,098.

Nevertheless, crimped metal binders have not been considered practicalfor quality power-driven industrial rotary end brushes, (end brushes areconstructed with a plurality of parallel bristles mounted in acup-shaped holder so that they extend generally parallel to the axis ofbrush rotation but flare radially under the centrifugal force of poweroperation) since a brush face formed from bristle material held in thismanner conforms roughly to the shape of the crimped binder resulting inan irregular brush face. An irregular brush face is generallyundesirable in quality power-driven industrial rotary end brushesbecause those portions of the bristle bundle that depart from orprotrude out of a generally circular blllSII face configuration areincreasingly subject to long bristle fracture and can cause unevenbrushing and/or objectionable vibration.

I have overcome these difficulties with the brush construction of thepresent invention, which, although it does not provide a perfectlycircular brush face, provides a brush face which is generally circular.The degree to which my brush face departs from a perfect circle isrelatively small and I have found it has insignificant consequences inoperation, primarily because relatively few bristles are involved andthey are evenly distributed in a balanced generally circularconfiguration about the brush face perimeter. At the same time, I havefound that the same banded bristle bundle (bristle cartridge hereafter)which is satisfactory for an industrial power driven rotary end brushaccording to the present invention can be used as a component for agreat variety of different rotary brushes with various beneficialresults so that it serves as an interchangeable constructional modulefor the construction of a varied line of brush types by an industrialbrush manufacturer, reducing the need for a plurality of difierent typesof bristle binding equipment and operations and lending simplicity tothe manufacturing procedures for such brushes.

Another advantage of the present invention is that the bristle ends maybe registered prior to binding and, upon binding,

I will maintain their alignment to form a relatively smooth brush facewhich requires relatively little or no finish grinding or trimming bycomparison to other bristle-binding techniques.

A further advantage is that the binder may be made of a relatively highthennal conducting metal, such as copper, which acts as a heat sink toconduct heat away from the point where the bristles emerge from theholder, so that bristle cartridges so bound may be used to advantage inrotary brushes having holders, collars and/or bridles of plastic orother relatively low melting point materials.

A still further advantage is that the bristle cartridge is otherwisewell suited for construction of brushes of the type wherein a smoothconvexly curved reinforced elastomeric collar encirclesthe bristleswhere they emerge from the bristle holder so that very durable brushesmay be constructed as disclosed in my copending US. Pat. applicationSer. No. 763,238.

Furthermore, the bristle cartridge is otherwise well suited to mountingin plastic holders since the metal binder relieves stresses that wouldotherwise be taken up by the plastic holder and because the cartridgemay be mounted in the holder with epoxy adhesive or the like, ratherthan with solder or by some other substance which would be deleteriousor inappropriate to the plastic.

These and other advantages, and objects of this invention, will beapparent to persons skilled in the art from the following description,claims and drawings. To theaccomplishment of the foregoing and relatedends, the invention then comprises the features hereinafter fullydescribed and particularly pointed out in the claims, the followingdescription and annexed drawing setting forth in detail certainillustrative embodiments of the invention, these being indicativehowever of but a few of the various ways in which the principles of thepresent invention may be employed.

BRIEF DESCRIPTION OF DRAWING In the annexed drawing:

FIG. 1 is an elevational partially sectioned view of a rotary end brushaccording to my invention, said brush having a corrugated metal-bandedbristle bundle held in a metal cupshaped holder.

FIG. 2 is a transverse section taken on the line 2-2 of FIG. 1.

FIG. 3 is a transverse section taken on the line 3-3 of FIG. 1.

FIG. 4 is an exploded view of the brush shown in FIG. 1.

FIG. 5 is an elevational partially sectioned view of another embodimentof the present invention comprising a rotary end brush having acorrugated metal-banded bristle bundle encircled with an O-ring andreceived in the cup portion of a cupshaped holder having a plastic cupportion.

FIG. 6 is a transverse section taken on the line 6--6 of FIG. 5.

FIG. 7 is a partially exploded view of the brush shown in FIG. 5.

FIG. 8 is an elevational partially sectioned view of a furtherembodiment of the present invention comprising two annular hub elementsof a wheel-type rotary brush according to my invention which is formedof a plurality of such annular hub elements which are plastic andassembled end to end in axial interlocking alignment. Each of theelements includes an annular plastic holder and a plurality ofcorrugated metal-banded bristle bundles encircled with O-rings andmounted in radial apertures in the holder.

FIG. 9 is a transverse section taken on the line 9-9 of FIG. 8.

FIG. 10 is a transverse section taken on the line l0 10 of FIG. 9.

DESCRIPTION OF PREFERRED EMBODIMENTS Referring now more particularly tothe drawing, and especially FIGS. I to 4 inclusive thereof, theembodiment of the invention there illustrated comprises an end brush 1having a metal holder 2 in the form of a cup portion 3 with an axiallyextending stem or spindle portion 4 adapted to be received and grippedby the chuck of an appropriate power tool. A bristle cartridge 5comprised of a bundle of crimped wire bristle material 6 tightlycompacted at one end by a rigid corrugated metal band 7 is mounted inthe cup portion 3, retained there by an adhesive such as epoxy resincement, and extends outwardly therefrom to provide a brush face 8 whichis generally circular but which has six substantially regularly spacedpointed portions 9 extending beyond the circular main body 10 of thebundle (represented by a broken line in FIG. 3) so that the bristle face8 has a starlike configuration. The points 9 of the brush face 8 areevenly distributed about the periphery of the brush face in a generallycircular configuration and contain a relatively low concentration ofbristles by comparison to the circular main bristle body 10. Thisuniquely shaped brush face 8 results from the unique shape of the binderring 7.

The bristle cartridge 5 (also referred to as the bristle module" 5) isformed by placing one end of a precut bundle 6 of crimped wire bristlesin a seven-sixteenths inch length of 20 gage copper tubing (wallthickness 0.035 inch) having an outer diameter of nine-sixteenths inch.The tubing is then simultaneously crimped inwardly at six regularlyspaced intervals (as with a six jaw chuck) to form corrugations ofsubstantially equal width and depth so that the binder ring 7 has across section resembling a spur gear having an outer diameter of aboutone-half inch, a circular pitch taken at the outer diameter of the gearof about 11/12 inch, and a total tooth depth of about one-sixteenthinch. The lands 11 between the gear teeth 12 are relatively wide so thatthe gear teeth 12 themselves have an average outer width of about threethirtyseconds. Accordingly, the average inner width of each gear tooth12 is about one thirty-second inch so that relatively few bristleslocate in the tooth portions 12 of the binder ring 7. The bristle bundle6 tends to assume the shape of the binder ring 7 which accounts for thepoints on the generally circular brush face 8. (It should be noted thatany references to gears or the like herein are made for convenience ofnotation and without regard to whether the object described couldactually function as a gear.)

A second embodiment of the present invention is shown in FIGS. 5 to 7employing a bristle module similar to that shown in FIGS. 1 to 4, thatembodiment comprising a rotary end brush 13 having a holder 14 with apolymeric or plastic cup portion 15 molded on a disclike anchor portion16 at one end of an axially extending stem 17 or spindle. The anchorportion 16 is provided with bosses 18 to prevent the plastic cup 15 fromrotating independently of the stem 17. A bristle module 19 comprised ofa bundle 20 of crimped wire bristle material bound at one end by acorrugated band 21 of metal is retained at that end in the cup portion15 by an adhesive 27 such as epoxy resin cement. The bristle module 19is essentially identical to the module 5 described in FIGS. 1 to 4,having a cross section resembling a six tooth spur gear. The plastic cup15 portion has two splines 26 on its cylindrical inner surface 22 whichproject into the spaces between the gear teet 23 keying in the adhesive27 to prevent the bristle module 19 from turning in the cup 15.

A toroidal rubber collar 23, preferably an O-ring, encircles thebristles 20 where they emerge from the binder ring 21. The O-ring collar23 is located inside the cup so that the cup 15 reinforces the O-ring 23against unwanted expansion. This collar 23 serves to protect thebristles 20 and plastic cup 15 from one another and to prevent sharpflexing of the bristles 20 under centrifugal force during brushrotation. The lip of the cup 15 has a slight counterbore to accommodatethe O- ring 23, and that lip is swaged inwardly to hold the O-ring 23 inplace,

The toroidal rubber collar 23 should be of an elastomeric material,preferably a copolymer of butadiene and acrylonitrile preferably with ahardness of about 70 Shore A durometer, but between about 50 and 90Shore A durometer. The surface 24 of the collar 23 which engages thebristles during brush operation should be smooth with a convex curvaturehaving a sectional diameter on the order of no less than about onethirty-second inch (a radius of curvature of no less than about onesixty-fourth inch) and preferably about one-eighth inch.

The cup portion 15 of the holder 14 is of a polymeric material,consisting essentially of a solid synthetic resin such as nylon,polypropylene or high impact styrene.

The invention has, thus far, been described with reference to V1 inch(outer diameter) bristle modules for use in it inch end brushes. It is,however, not limited to modules of this size and similar bristle moduleswithin this invention can be constructed for use in end brushes ofthree-fourths inch and l inch (inner cup diameter) or larger. In eachinstance, the pitch will be relatively constant (as low as one-tenth 7rinch and preferably about 1r/12 inch at the outer diameter) so that thenumber of teeth increase as the brush diameter increases. Nine teeth arepreferred in the 34-inch brush and twelve teeth are preferred in the 1inch brush, whereas the total tooth depth remains relatively constant(about one-sixteenth inch), as does the gage of the band material andtooth thickness so that those portions of the brush face which lieoutside the circular main bristle body are regularly spaced in acircular configuration and do not contain very many bristles, nor dothey protrude very far beyond the circular main bristle body. It will bereadily apparent to persons of ordinary skill in the art that in the 3inch and 1 inch brushes, the pitch of the gearlike binder ring may belengthened (and the number of teeth reduced) as the bundle sizeincreases without departing substantially from a generally circularbrush face. Nevertheless, this will generally be undesirable because itis likely to result in a looser binding which can only be avoided byincreasing the tooth depth, thereby increasing the distance beyond thecircular main bristle body by which the portions outside such bodyproject. This is seen to be even less desirable in view of the fact thatthe larger bundles are necessarily less tightly packed because of thereduction in the ratio of the cross-sectional area of the uncrimped ringto the crimped ring as ring diameter increases. Thus, while it isapparent that there is little to be gained by increasing the pitch ofthe gearlike binder, it may be helpful to decrease the pitch as largerbristle modules are constructed, especially where bristle modules aredesired having diameters larger than conventional end brush diameters(about k-l inch) in order to bind the bristles with sufficient tightnessto hold them securely in the ring.

Neither is the present invention limited in its application solely toend brushes, since the bristle modules heretofore described are suitablefor use in other rotary brushes such as relatively narrow face wheelbrushes of the type generally used for cleaning, polishing and deburringoperations, or even larger rotary brushing tools of relatively greataxial extent for use in sweeping, scrubbing, polishing, cleaning orother treatment of large flat surfaces such as floors or roadways.

Thus, a further embodiment of the present invention is illustrated inFIGS. 8 to 10 comprising a power-driven rotary sweeping brush 30 formedfrom a plurality of similar or identical relatively narrow annular brushelements 31 assembled end to end in coaxial interlocking relation andadapted for mounting on a drive shaft 32.

A plurality of bristle modules 33 in accordance with the presentinvention are mounted in generally cylindrical cavities 34 spaced aboutthe periphery of a one piece annular holder 35. The bristle modules 33are substantially the same or similar to those discussed in connectionwith FIGS. 1 to 4, and 5 to 7 above, being comprised of a bundle ofbristle material 36 tightly bound at one end by a corrugated band ofmetal 37 having a cross section resembling a spur gear with a circularpitch (at the outer diameter) of about 1r/l2 inch and a total toothdepth of about one-sixteenth inch. In the sweeper brush shown, tampicofibers are employed as are generally preferred, although wire and otherbrush material may be used or will be preferred in other similar brushesfor different purposes, as will be apparent to persons of ordinary skillin the art. The bristle modules 33 are fixed in the hub cavities 34 withepoxy resin or some other suitable adhesive.

The holder 35 is generally annular and has a hub portion 38 and a holderportion 39 located abaxially from the hub portion 38. Cylindricalbristle module receiving cavities 34 are located in the radially outerface 40 of the holder portion 39. The hub portion 38 has a central shaftreceiving opening 41 to accommodate the drive shaft 32.

One end of the hub portion 38 is shaped to complement its axiallyopposed end so that one such brush element 31 interlocks coaxially withthe correspondingly opposed side of a like brush element 31. In thismanner, a brush of relatively great axial extent (and having a verybroad cylindrical brush face) may be built up from a plurality ofrelatively narrow brush elements 31. The holder 35 is formed of asuitable polymeric material, preferably a solid synthetic resin such asnylon, polypropylene or high impact styrene.

An O-ring 42 or other toroidal collar is preferably employed asdescribed hereinabove and in my copending U.S. Pat. application Ser. No.763,238, to encircle the bristles 36 where they emerge from thecorrugated binder 37. The O-ring 42 is located within the bristle modulecavity 34 of the holder portion 39 so that the relatively rigid holder35 reinforces the O- ring 42 against expansion of its outer diameter. Inthis manner, the plastic holder 35 and the bristles 36 are protectedfrom one another and the bristles 36 are protected against sharp flexingduring operation. Protection of the holder from the bristles isincreasingly important as more abrasive brush fill material is employed,as with crimped wire bristles.

The sweeping brush 30 illustrated in FIGS. 8 to 10 of the above isrepresentative of a number of similarly constructed brushes within thepresent invention embodying modifications adapting the brushes tovarious particular purposes. In some cases, the bristle modules may beangled to the axis of the drive shaft so that a side-to-side sweepingefl'ect results when the brush rotates. In other cases, the bristlemodules may be grouped closely together throughout the brush to form acontinuous composite brush face, or small groups of bristle modules maybe grouped in a variety of ways to form various tufted brush faceconfigurations. Furthermore, a wheel brush may be formed with a singleannular holder having one or more rows of bristle modules, all as willbe apparent to persons of ordinary skill in the art.

The binder rings of the bristle modules of the present invention arepreferably formed of copper oralumin um or other material having a highthermal conductivity such as in excess of 100 B.t.u. per hour per squarefoot per degree F. per foot, and preferably in excess of 200 B.t.u. perhour per square foot per degree F. per foot. This conductive band actsas a heat sink tending to draw heat away from portions of the bristlescloser to the brush face. During brushing operations, the bristles tendto be hotter towards the brush face and cooler away from the brush face.This tendency, however, does not result in a regular reduction intemperature along the entire bristle length, since the exposed portionsof the bristles are cooled by air during rotation and the enclosedportions of the bristles tend to cool relatively slowly. The temperatureprofile of the bristles at any given time is further complicated by theintermittent nature of brushing operations where, for example, a brushmight be alternately driven under power at no load for 5 seconds andthen placed under load for 10 seconds intermittently over a period ofperhaps 10 minutes. Under these conditions, the enclosed portions of thebristles can build up temperatures which, after the brush has rotatedfor 5 seconds under no load, may actually be higher than the temperatureof the exposed portions of the bristles. It is believed that the segmentof the enclosed bristle portion which attains the highest temperaturesis that segment which is slightly inside the rim of the holder. Andwhile the average temperature of the enclosed portion of the bristle maystay within acceptable limits, the temperature of that particularsegment at the rim of the holder may reach temperatures which aredeleterious to the bristles, the plastic cup, and/or the O-ring.Accordingly, by employing a highly conductive metal binder on thebristle module, 1 can conduct heat away from the rim area and lower thebristle temperature at the rim of the holder. Inasmuch as this is anexceptionally high wear area in such brushes, this lowered temperatureis believed to have a beneficial effect on brush life.

The bristle module of the present invention is suitable for all types ofbrush fill material including tampico fiber, plastic coated wire, andplastic monofilaments like nylon fiber. It is also suited for formingbristle modules from straight wire which, in the past, has usuallynecessarily been knotted around an anchor ring. In addition, the exposedbristles may be encapsulated in polyurethane or the like. See Han: etal. US. Pat. No. 3,142,081.

The bristle module of the present invention and brushes formed therewithlend themselves to efficient and low-cost production methods. Forexample, in the construction ofprior art end brushes in which thebristles are mounted in solder in the holder cup, it is necessary tofirst cut a bundle of bristles to size at a first station, whereupon thebundle is bound with a temporary binding and transported to a secondstation. At the second station, the binding is removed and the bristlesare tightly compressed at one end and inserted into the cup. Lastly, thebrush face is ground or trimmed smooth.

Construction of brushes according to the present invention commences byfirst forming a bundle of bristle material; inserting one end of thebundle into a cylindrical metal band; deforming the band inwardly atregularly spaced intervals to form corrugations of substantiallyidentical width and depth and thereby tightly compact the bristlematerial at that end; and mounting the banded end of the bristle bundlein the holder portion of the rotary brush, preferably with adhesive suchas epoxy or the like. The bristles may be aligned with their ends inregistry prior to binding so that when bound in the manner of thepresent invention they provide a relatively fiat brush face requiringlittle or no finish grinding.

Brushes formed according to the present invention thus may bemanufactured in fewer steps by eliminating the need to apply and removea temporary binding since the metal binder forms a pennanent part of thebrush. Neither is it necessary to subsequently compact the bristlessince this is accomplished in the binding step. Furthermore, the needfor extensive finish grinding is eliminated, handling is greatlysimplified, and various other advantages accrue as will be apparent topersons of ordinary skill in the art.

Having thus described my invention, 1 claim:

I. A power-driven industrial rotary end brush comprising a cup-shapedholder; 1

a bundle of brush bristle material; and

a rigid corrugated cylindrical metal band enclosing and tightlycompacting one end of said bristle bundle, the corrugations in said bandbeing substantially identical and comprised of alternating ridges andgrooves extending generally parallel to the longitudinal axis of saidbristle bundle, the other end of said bristle bundle extending from saidcorrugated band to provide a composite generally circular brush face,said banded bristle bundle mounted with its banded end secured in saidholder.

2. A rotary end brush as recited in claim 1 wherein said corrugatedmetal band has an outer diameter of about one-half inch or greater.

3. A rotary end brush as recited in claim 1 further comprising a collarencircling said bundle of bristle material where it emerges from saidband, said collar having a smooth convexly curved bristle supportsurface for supporting said bristles when they flare radially duringbrush rotation, said collar being of an elastomeric material with ahardness in excess of about 50 Shore A durometer, and means forreinforcing said collar against substantial expansion during use of saidbrushin power machinery.

4. A rotary end brush as recited in claim 3 wherein said elastomericmaterial has a hardness between about 50 and Shore A durometer.

5. A rotary end brush as recited in claim 3 wherein said collar is anO-ring.

6. A rotary end brush as recited in claim 3 wherein the radius ofcurvature of said bristle support surface is not less than onethirty-second inch.

7. A rotary end brush as recited in claim 3 wherein said collar is anO-ring constructed of elastomeric material having a hardness betweenabout 50 and 90 Shore A durometer.

8. An improved rotary brush as recited in claim 7 wherein the majoringredient of said elastomeric material is a copolymer of butadiene andacrylonitrile.

9. A rotary end brush as recited in claim 3 wherein the material fromwhich the cup portion of said holder is constructed consists essentiallyof a polymer.

10. A rotary end brush as recited in claim 3 wherein the material fromwhich the cup portion of said holder is constructed consists essentiallyof a solid synthetic resin.

11. A rotary end brush as recited in claim 3 wherein the material fromwhich the cup portion of said holder is constructed consists essentiallyof a solid synthetic resin selected from the group consisting of nylon,polypropylene and high impact styrene.

12. A rotary end brush as recited in claim 9 wherein said collar is anO-ring.

13. A rotary end brush as recited in claim 12 wherein the basicingredient of said elastomeric material is a copolymer of butadiene andacrylonitrile having a hardness between about 50 and 90 Shore Adurometer.

14. A rotary end brush as recited in claim 13 wherein said polymer isselected from the group consisting of nylon, polypropylene and highimpact styrene.

15. A power-driven industrial rotary brush comprising a circular holder;

a bundle of brush bristle material; and

a rigid corrugated cylindrical metal band enclosing and tightlycompacting one end of said bristle bundle, the corrugations in said bandbeing substantially identical and comprised of alternating ridges andgrooves extending generally parallel to the longitudinal axis of saidbristle bundles, the other end of said bristle bundle extending fromsaid corrugated band to provide a composite generally circular brushface, said banded bristle bundle mounted with its banded end secured insaid holder.

16. A rotary brush as recited in claim 15 wherein the material fromwhich said holder is constructed consists essentially of a polymer.

17. A rotary brush as recited in claim 15 wherein the material fromwhich said holder is constructed consists essentially of a solidsynthetic resin.

18. A rotary brush as recited in claim 17 wherein said resin is selectedfrom the group consisting of nylon, polypropylene and high impactstyrene.

19. A rotary brush as recited in claim 15 further comprising a collarencircling said bundle of bristle material where it emerges from saidband, said collar having a smooth convexly curved bristle supportsurface for supporting said bristles when they bend outwardly duringbrush use, said collar being of an elastomeric material with a hardnessin excess of about 50 Shore A durometer, and means for reinforcing saidcollar against substantial expansion during use of said brush in powermachinery.

20. A rotary brush as recited in claim 19 wherein said collar is anO-ring.

21. A rotary brush as recited in claim 20 wherein the O-ring has asectional diameter of not less than about one-sixteenth inch.

22. A rotary brush as recited in claim 21 wherein the material fromwhich said holder is constructed consists essentially of a polymer.

23. A rotary brush as recited in claim 21 wherein the material fromwhich said holder is constructed consists essentially of a solidsynthetic resin.

24. A rotary brush as recited in claim 23 wherein said resin is selectedfrom the group consisting of nylon, polypropylene and hrghrmpactstyrene

1. A power-driven industrial rotary end brush comprising a cup-shapedholder; a bundle of brush bristle material; and a rigid corrugatedcylindrical metal band enclosing and tightly compacting one end of saidbristle bundle, the corrugations in said band being substantiallyidentical and comprised of alternating ridges and grooves extendinggenerally parallel to the longitudinal axis of said bristle bundle, theother end of said bristle bundle extending from said corrugated band toprovide a composite generally circular brush face, said banded bristlebundle mounted with its banded end secured in said holder.
 2. A rotaryend brush as recited in claim 1 wherein said corrugated metal band hasan outer diameter of about one-half inch or greater.
 3. A rotary endbrush as recited in claim 1 further comprising a collar encircling saidbundle of bristle material where it emerges from said band, said collarhaving a smooth convexly curved bristle support surface for supportingsaid bristles when they flare radially during brush rotation, saidcollar being of an elastomeric material with a hardness in excess ofabout 50 Shore A durometer, and means for reinforcing said collaragainst substantial expansion during use of said brush in powermachinery.
 4. A rotary end brush as recited in claim 3 wherein saidelastomeric material has a hardness between about 50 and 90 Shore Adurometer.
 5. A rotary end brush as recited in claim 3 wherein saidcollar is an O-ring.
 6. A rotary end brush as recited in claim 3 whereinthe radius of curvature of said bristle support surface is not less thanone thirty-second inch.
 7. A rotary end brush as recited in claim 3wherein said collar is an O-ring constructed of elastomeric materialhaving a hardness between about 50 and 90 Shore A durometer.
 8. Animproved rotary brush as recited in claim 7 wherein the major ingredientof said elastomeric material is a copolymer of butadiene andacrylonitrile.
 9. A rotary end brush as recited in claim 3 wherein thematerial from which the cup portion of said holder is constructedconsists essentially of a polymer.
 10. A rotary end brush as recited inclaim 3 wherein the material from which the cup portion of said holderis constructed consists essentially of a solid synthetic resin.
 11. Arotary end brush as recited in claim 3 wherein the material from whichthe cup portion of said holder is constructed consists essentially of asolid synthetic resin selected from the group consisting of nylon,polypropylene and high impact styrene.
 12. A rotary end brush as recitedin claim 9 wherein said collar is an O-ring.
 13. A rotary end brush asrecited in claim 12 wherein the basic ingredient of said elastomericmaterial is a copolymer of butadiene and acrylonitrile having a hardnessbetween about 50 and 90 Shore A durometer.
 14. A rotary end brush asrecited in claim 13 wherein said polymer is selected from the groupconsisting of nylon, polypropylene and high impact styrene.
 15. Apower-driven industrial rotary brush comprising a circular holder; abundle of brush bristle material; and a rigid corrugated cylindricalmetal band enclosing and tightly compacting one end of said bristlebundle, the corrugations in said band being substantially identical andcomprised of alternating ridges and grooves extending generally parallelto the longitudinal axis of said bristle bundles, the other end of saidbristle bundle extending from said corrugated band to provide acomposite generally circular brush face, said banded bristle bundlemounted with its banded end secured in said holder.
 16. A rotary brushas recited in claim 15 wherein the material from which said holder isconstructed consists essentially of a polymer.
 17. A rotary brush asrecited in claim 15 wherein the material from which said holder isconstructed consists essentially of a solid synthetic resin.
 18. Arotary brush as recited in claim 17 wherein said resin is selected fromthe group consisting of nylon, polypropylene and high impact styrene.19. A rotary brush as recited in claim 15 further comprising a collarencircling said bundle of bristle material where it emerges from saidband, said collar having a smooth convexly curved bristle supportsurface for supporting said bristles when they bend outwardly duringbrush use, said collar being of an elastomeric material with a hardnessin excess of about 50 Shore A durometer, and means for reinforcing saidcollar against substantial expansion during use of said brush in powermachinery.
 20. A rotary brush as recited in claim 19 wherein said collaris an O-ring.
 21. A rotary brush as recited in claim 20 wherein theO-ring has a sectional diameter of not less than about one-sixteenthinch.
 22. A rotary brush as recited in claim 21 wherein the materialfrom which said holder is constructed consists essentially of a polymer.23. A rotary brush as recited in claim 21 wherein the material fromwhich said holder is constructed consists essentially of a solidsynthetic resin.
 24. A rotary brush as recited in claim 23 wherein saidresin is selected from the group consisting of nylon, polypropylene andhigh impact styrene.